1. Field of the Invention
The invention relates to a large-area LCD billboard for outdoor advertising, whereby the luminosity of the reflective LCD elements of the board depends on the intensity and direction of the lighting, and an artificial lighting device with lamps is assigned to the board for this purpose, for times when the sunlight is insufficient, which lamps illuminate the board from the viewer side, if necessary. The abbreviation LCD stands for “liquid crystal display.” The artificial light is supposed to have essentially the same effect as sunlight on the LCD elements, in the end result.
2. Descrtion of Related Art
In WO 02/073 57/A2, lamps for lighting an advertising image produced in conventional manner are indicated. The lamps light the advertising image either from the viewer side, or the advertising image is lighted from the rear, if the advertising poster, in each instance, is at least translucent.
In the reference WO 01/88 688 A1, an LCD board is described, to which lighting elements are assigned, which are regulated in accordance with the incident sunlight, using a control unit.
However, when the sun shines, shadows of the lighting elements can show on the LCD board.
On LCD boards that are set up on roadways or on building walls, and the surface of which can have a width and length of several meters (“large-area”), it is possible to display advertising motifs in any desired sequence, for example from the central office of an advertising company, and to delete them again. The individual LCD elements together produce a large-area image, the luminosity of which, in other words its brightness and colors, is produced or reinforced for the intended purpose, namely advertising that is visible over a great distance, only by means of incident outside light.
The effect of the outside light seems to consist in the fact that the light is reflected at the LCD elements, which are often protected behind a glass pane. During the day, sunlight is completely sufficient as the outside light. However, the luminosity of the billboard decreases to the point of becoming pale if the daylight is relatively slight, for example due to dark clouds or during dusk, or when it is entirely absent at night. For these times of insufficient daylight, it has been the practice until now to provide artificial lighting devices with lamps on the LCD billboards, which lamps illuminate the board on the viewer side, for example at a slant from above, like the sun, and cause the LCD elements to luminesce in their color, in each instance.
The lighting devices, i.e. their lamps are installed in such a manner that they do not impair the image effect of the advertising motif, in each instance. The lamps are therefore affixed outside the edge of the billboard, in such a manner that they do not stand between the viewer and the advertising motif—within a predetermined angle range in front of the billboard—in other words do not cover it. On the other hand, however, the lighting devices are supposed to be positioned in such a manner that they can illuminate the board from the viewer side, like the sun. As stated, this can have the result that the lighting devices show as shadows on the billboard in daylight.